The ability to easily remotely steer, guide and/or manipulate instruments and tools is of interest in a wide variety of industries and applications, in particular where it is desired to navigate an instrument or tool into a workspace that is not easy to manually navigate by hand or that might otherwise present a risk or danger. These can include situations where the targeted site for the application of a tool or instrument is difficult to access, e.g., certain surgical procedures, the manufacture or repair of machinery, or even commercial and household uses, where manual access to a targeted site is restricted or otherwise. Other situations can include e.g., industrial applications where the work environment is dangerous to the user, such as workspaces exposed to dangerous chemicals. Still other situations can include e.g., law enforcement or military applications where the user may be at risk, such as deployment of a tool or instrument into a dangerous or hostile location.
Using surgical procedures as an illustrative example, procedures such as endoscopy and laparoscopy typically employ instruments that are steered within or towards a target organ or tissue from a position outside the body. Examples of endoscopic procedures include sigmoidoscopy, colonoscopy, esophagogastroduodenoscopy, and bronchoscopy. Traditionally, the insertion tube of an endoscope is advanced by pushing it forward and retracted by pulling it back. The tip of the tube may be directed by twisting and general up/down and left/right movements. Oftentimes, this limited range of motion makes it difficult to negotiate acute angles (e.g., in the recto sigmoid colon), creating patient discomfort and increasing the risk of trauma to surrounding tissues. Laparoscopy involves the placement of trocar ports according to anatomical landmarks. The number of ports usually varies with the intended procedure and number of instruments required to obtain satisfactory tissue mobilization and exposure of the operative field. Although there are many benefits of laparoscopic surgery, e.g., less postoperative pain, early mobilization, and decreased adhesion formation, it is often difficult to achieve optimal retraction of organs and maneuverability of conventional instruments through laparoscopic ports. In some cases, these deficiencies may lead to increased operative time or imprecise placement of components such as staples and sutures. Steerable catheters are also well known for both diagnostic and therapeutic applications. Similar to endoscopes, such catheters include tips that can be directed in generally limited ranges of motion to navigate a patient's vasculature.
There have been many attempts to design endoscopes and catheters with improved steerability. For example, U.S. Pat. No. 3,557,780 to Sato; U.S. Pat. No. 5,271,381 to Ailinger et al.; U.S. Pat. No. 5,916,146 to Alotta et al.; and U.S. Pat. No. 6,270,453 to Sakai describe endoscopic instruments with one or more flexible portions that may be bent by actuation of a single set of wires. The wires are actuated from the proximal end of the instrument by rotating pinions (Sato), manipulating knobs (Ailinger et al.), a steerable arm (Alotta et al.), or by a pulley mechanism (Sato). U.S. Pat. No. 5,916,147 to Boury et al. discloses a steerable catheter having four wires that run within the catheter wall. Each wire terminates at a different part of the catheter. The proximal ends of the wires extend loosely from the catheter so that the physician may pull them. The physician is able to shape and steer the catheter by selectively placing the wires under tension.
Although each of the devices described above is remotely steerable, the range of motion is generally limited. Moreover, it is difficult to transmit torque between links by rotating the device around the central axes of each link in such devices while still allowing components to pivot with respect to one another. Consequently, it would be advantageous for such a device to be capable of transferring torque about the central axis of each link, while preserving the capability of components to pivot with respect to each other. Further, it would be advantageous for components of such a device to pivot with respect to each other instead of moving laterally relative to each other (i.e. parallelogramming). Still further, it would be advantageous for such a device to have a locking mechanism capable of preventing movement of the device. Such a device would have widespread application in guiding, steering, and/or manipulating instruments and tools across numerous industries. Such a device would also of itself have entertainment, recreational, and educational value.